Conventionally, as information-writable DVDs (digital versatile discs), which are large-capacity optical discs, DVD-R (DVD-recordable) on which information can be written once, DVD-RW (DVD-rewritable) on which information can be rewritable, and DVD-RAM (DVD-random access memory) are provided. As for DVD-R and DVD-RW of these optical discs, if video data is recorded in a format conformable to the DVD video format, the data can be reproduced by a playback-only optical disc player. This standard enables reading of data recorded on a disc in a computer that processes data, by supporting the standard of universal disk format (UDF).
FIGS. 1A to 1C are views showing a logical format of an optical disc based on the DVD video format. The optical disc based on this format has its information recording surface sectioned into a lead-n area, a data zone, and a lead-out area, from the innermost side, which is the leading side, and desired video data is recorded in the data zone, as shown in FIG. 1A.
The data zone is sectioned into, from the lead-in side, a UDF (universal disk format) area A1, which is a file system area with a UDF bridge structure described therein, a VMG (video manager) area A2, which is a DVD management information area, and a real-time recording area A3. The UDF area and VMG area are management information recording areas for managing files based on video data recorded on this optical disc. Of these UDF area and VMG area, the second management information recording area, that is, the VMG area, is an area corresponding to a file management system proper to the DVD video format, and TOC information as management information for managing the whole video data recorded in the real-time data recording area A3 is recorded in this area. On the other hand, the first management information recording area, that is the UDF area A1, is an area corresponding to a file management system based on a computer, and management information for managing the whole video data recorded in the real-time data recording area A3 in a format that realizes compatibility with the file system in the computer is recorded in this area.
The real-time data recording area A3 is a user area for recording actual data, and video data is recorded by each VTS (video title set, hereinafter suitably referred to as title) as a unit in this area, as shown in FIG. 1B. 99 VTSs can be provided at the maximum. This VTS includes, from the leading side, VTSI (video title set information), VTSM VOBS (video object set for the VTSM), VTSTT VOBS (video object set for titles in a VTS), and VTSI BUP (backup of VTSI), as shown in FIG. 1C. In VTSTT VOBS, video data based on the MPEG (Moving Picture Experts Group) 2 format, which is actual data, is recorded. In VTSI, recording position information or the like, which is management information for managing video data based on this actual data, is recorded. In VTSTT VOBS, a title menu of video data is recorded. VTSTT VOBS is optional. VTSI BUP is a backup for VTSI.
With an optical disc of this type, when accessing data by using a computer, a desired file can be retrieved and reproduced on the basis of UDF, and when reproducing data by using a DVD player, a desired file can be retrieved and reproduced on the basis of VMG.
As a system for writing video data to such an optical disc, an incremental recording system (hereinafter referred to as INC system) or a restricted overwrite system (hereinafter referred to as ROW system) is used. The INC system is a system of sequentially recording video data. The ROW system is a system applied to an optical disc on which data can be overwritten. However, even in the ROW system, when recording data to an non-recorded area, video data is recorded sequentially. In the INC system and the ROW system, processing to the optical disc such as reservation is managed using RMA (recording management area) provided on the inner side of the lead-in area.
FIGS. 2A to 2H show recording procedure based on the INC system. In the INC system, it is defined that data can be written into a maximum of three areas at a time. Each of these areas is called R zone and each R zone is managed using RMA.
Specifically, in the case of recording a motion picture in the INC system, R zones are reserved first, as shown in FIG. 2A. In executing the reservation of R zones, an R zone 1 area, which forms a UDF area and a VMG area as a management information recording area, is defined, and then an R zone 2 area, which forms VTSI and VTSM VOBS of the leading VTS, is defined in a non-recorded area, which forms a real-time data recording area. The remaining non-recorded area is defined as an Invisible R zone area. In the INC system, by reserving these R zone 1 and R zone 2, the management information recording area is secured and the area forming VTSI and VTSM VOBS of the leading VTS is secured.
In the INC system, VTSTT VBOS based on actual data is formed by sequentially recording video data from the leading side of the Invisible R zone. Moreover, when recording of actual data for one title is completed by a user's instruction, VTSI BUP is recorded after the recording of this actual data, as shown in FIG. 2B. Then, again from the leading side, VTSI and VTSM VOBS are formed in the R zone 2, as shown in FIG. 2C, and the R zone 2 is closed. In this manner, one VTS is recorded on the optical disc in the INC system.
In the case of continuously recording the next title in the INC system, an R zone 3 is reserved in the remaining non-recorded area to secure VTSI and VTSM VOBS, and the Invisible R zone is defined, as shown in FIG. 2D. Then, after VTSTT VOBS is formed by recording actual data, VTSI BUP is formed, as shown in FIG. 2E, and VTSI and VTSM VOBS are formed in the previously secured area, as shown in FIG. 2F. In this manner, the subsequent VTS is recorded on the optical disc, as shown in FIG. 2G. In the INC system, in the case of recording subsequent titles, the non-recorded area is similarly defined and VTSs are sequentially recorded.
In the INC system, on the optical disc on which the real-time data recording area is formed by sequentially recording VTSs in this manner, a UDF area and a VMG area are formed by finalizing processing, and a lead-in area and a lead-out area are formed, as shown in FIG. 2H. This realizes compatibility with a playback-only optical disc. The formation of the UDF area and the VMG area is executed by generating UDF and VMG data from VTSI and VTSM VOBS of each title, then recording the data in the R zone 1, and closing the R zone 1.
FIGS. 3A to 3G show recording procedure based on the ROW system. In the ROW system, a recording area for lead-in, UDF, VMG, and VTSI and VTSM VOBS of the leading title is secured in advance by padding, as shown in FIG. 3A. Padding is the processing to secure an area by recording dummy data such as NULL.
As these areas are secured in this manner, in the ROW system, VTSTT VOBS based on actual data is formed by sequentially recording video data, as shown in FIG. 3B. As recording of actual data of one title is completed, VTSI BUP is subsequently recorded, as shown in FIG. 3B. Then, to secure a recording area for VTSI and VTSM VOBS of a subsequent title, padding processing is executed. Again from the leading side, VTSI and VTSM VOBS corresponding to the recording of this actual data are formed, as shown in FIG. 3C. In this manner, one VTS is recorded on the optical disc in the ROW system.
In the case of continuously recording the next title in the ROW system, VTSTT VOBS and VTSI BUP are formed by recording actual data, following the padding area formed by the VTS that is immediately before, as shown in FIG. 3D. To secure a recording area for VTSI and VTSM VOBS of a subsequent title, padding processing is executed. Next, VTSI and VTSM VOBS are formed, as shown in FIG. 3E, and the subsequent VTS is recorded on the optical disc, as shown in FIG. 3F. In the ROW system, in the case of recording subsequent titles, processing such as padding is similarly executed and VTSs are sequentially recorded.
In the ROW system, on the optical disc on which the real-time data recording area is formed by sequentially recording VTSs in this manner, a UDF area and a VMG area are formed by finalizing processing similar to that of the INC system, and a lead-in area and a lead-out area are formed, as shown in FIG. 3G. This realizes compatibility with a playback-only optical disc.
Generally, in the case of recording data in the DVD video format to a DVD-RW medium, a file system for managing an intermediate state is necessary. If only recording conformable to the DVD video standard is performed, information managing VTSs is held in the file system for the intermediate state. Therefore, when a VTS is deleted, which LSN (logical sector number) on the medium has become free is managed. By utilizing this information, it is possible to newly record data to this position.
For example, JP-A-14-063765 discloses a technique of recording information to a DVD-R along real time in such a manner that the information can also be reproduced by a player for a playback-only DVD where information is recorded irrespective of real time. According to this disclosed technique, in the case of recording information to a DVD-R while conforming to the DVD video standard including at least a VTS containing VOBS to be reproduced and the corresponding VTSI, and VMGI for controlling reproduction of one or plural VTSs, the VTS is recorded to the DVD-R, and after recording the VTS, temporary VMGI is generated as temporary control information corresponding to the recorded VTS and adapted for later forming VMGI and recording the VMGI to the DVD-R. The generated temporary VMGI is recorded to the DVD-R every time a VTS is recorded to the DVD-R. By thus generating temporary control information and temporarily recording the temporary control information to the write-once recording medium when unit recording information is recorded, and by accurately recording original management control information later by using the temporary control information containing the latest contents, even if plural units of recording information are recorded on the write-once recording medium, it is possible to execute information recording to the write-once recording medium along real time in conformity with the recording format for a playback-only recording medium, which is not assumed to record information along real time.
Conventionally, in the case of realizing the DVD video format in a video recording apparatus using a rewritable optical disc medium, typically, temporary reproduction management information is recorded at a fixed address and a file system and reproduction information conformable to the DVD video format are recorded at the time of finalizing. In this method, the fixed address is frequently accessed and the rewriting durability of the medium may be exceeded in a short time. Once this management information becomes unreadable, the entire management information of the disc will be lost.